serializers.py 文件源码

def get_default(self):
        """
        Override `get_default()` defined on `serializers.Field` class.

        In this case, if there are empty data for a serializer field, i.e.
        a nested field, try to populate it by retrieving the default value of
        each of their fields.
        """
        default = {}
        for k, v in self.fields.iteritems():
            try:
                default[k] = v.get_default()
            except serializers.SkipField:
                pass
        return default